diff options
| -rw-r--r-- | sys/netinet/tcp_input.c | 39 |
1 files changed, 22 insertions, 17 deletions
diff --git a/sys/netinet/tcp_input.c b/sys/netinet/tcp_input.c index 2c7d15368483..b1846822b207 100644 --- a/sys/netinet/tcp_input.c +++ b/sys/netinet/tcp_input.c @@ -287,6 +287,20 @@ kmod_tcpstat_add(int statnum, int val) counter_u64_add(VNET(tcpstat)[statnum], val); } +/* + * Make sure that we only start a SACK loss recovery when + * receiving a duplicate ACK with a SACK block, and also + * complete SACK loss recovery in case the other end + * reneges. + */ +static bool inline +tcp_is_sack_recovery(struct tcpcb *tp, struct tcpopt *to) +{ + return ((tp->t_flags & TF_SACK_PERMIT) && + ((to->to_flags & TOF_SACK) || + (!TAILQ_EMPTY(&tp->snd_holes)))); +} + #ifdef TCP_HHOOK /* * Wrapper for the TCP established input helper hook. @@ -2525,9 +2539,7 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so, TCPSTAT_INC(tcps_rcvacktoomuch); goto dropafterack; } - if ((tp->t_flags & TF_SACK_PERMIT) && - ((to.to_flags & TOF_SACK) || - !TAILQ_EMPTY(&tp->snd_holes))) + if (tcp_is_sack_recovery(tp, &to)) sack_changed = tcp_sack_doack(tp, &to, th->th_ack); else /* @@ -2597,8 +2609,7 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so, * duplicating packets or a possible DoS attack. */ if (th->th_ack != tp->snd_una || - ((tp->t_flags & TF_SACK_PERMIT) && - (to.to_flags & TOF_SACK) && + (tcp_is_sack_recovery(tp, &to) && !sack_changed)) break; else if (!tcp_timer_active(tp, TT_REXMT)) @@ -2610,8 +2621,7 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so, if (V_tcp_do_prr && IN_FASTRECOVERY(tp->t_flags)) { tcp_do_prr_ack(tp, th, &to); - } else if ((tp->t_flags & TF_SACK_PERMIT) && - (to.to_flags & TOF_SACK) && + } else if (tcp_is_sack_recovery(tp, &to) && IN_FASTRECOVERY(tp->t_flags)) { int awnd; @@ -2684,8 +2694,7 @@ enter_recovery: * snd_ssthresh is already updated by * cc_cong_signal. */ - if ((tp->t_flags & TF_SACK_PERMIT) && - (to.to_flags & TOF_SACK)) { + if (tcp_is_sack_recovery(tp, &to)) { tp->sackhint.prr_delivered = tp->sackhint.sacked_bytes; } else { @@ -2697,8 +2706,7 @@ enter_recovery: tp->sackhint.recover_fs = max(1, tp->snd_nxt - tp->snd_una); } - if ((tp->t_flags & TF_SACK_PERMIT) && - (to.to_flags & TOF_SACK)) { + if (tcp_is_sack_recovery(tp, &to)) { TCPSTAT_INC( tcps_sack_recovery_episode); tp->snd_recover = tp->snd_nxt; @@ -2790,8 +2798,7 @@ enter_recovery: * from the left side. Such partial ACKs should not be * counted as dupacks here. */ - if ((tp->t_flags & TF_SACK_PERMIT) && - (to.to_flags & TOF_SACK) && + if (tcp_is_sack_recovery(tp, &to) && sack_changed) { tp->t_dupacks++; /* limit overhead by setting maxseg last */ @@ -3973,8 +3980,7 @@ tcp_do_prr_ack(struct tcpcb *tp, struct tcphdr *th, struct tcpopt *to) * (del_data) and an estimate of how many bytes are in the * network. */ - if (((tp->t_flags & TF_SACK_PERMIT) && - (to->to_flags & TOF_SACK)) || + if (tcp_is_sack_recovery(tp, to) || (IN_CONGRECOVERY(tp->t_flags) && !IN_FASTRECOVERY(tp->t_flags))) { del_data = tp->sackhint.delivered_data; @@ -4018,8 +4024,7 @@ tcp_do_prr_ack(struct tcpcb *tp, struct tcphdr *th, struct tcpopt *to) * accordingly. */ if (IN_FASTRECOVERY(tp->t_flags)) { - if ((tp->t_flags & TF_SACK_PERMIT) && - (to->to_flags & TOF_SACK)) { + if (tcp_is_sack_recovery(tp, to)) { tp->snd_cwnd = tp->snd_nxt - tp->snd_recover + tp->sackhint.sack_bytes_rexmit + (snd_cnt * maxseg); |